From bba0bdd7ad4713d82338bcd9b72d57e9335a664b Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Wed, 4 Mar 2015 10:31:47 +0100 Subject: Defer processing of REQ_PREEMPT requests for blocked devices SCSI transport drivers and SCSI LLDs block a SCSI device if the transport layer is not operational. This means that in this state no requests should be processed, even if the REQ_PREEMPT flag has been set. This patch avoids that a rescan shortly after a cable pull sporadically triggers the following kernel oops: BUG: unable to handle kernel paging request at ffffc9001a6bc084 IP: [] mlx4_ib_post_send+0xd2/0xb30 [mlx4_ib] Process rescan-scsi-bus (pid: 9241, threadinfo ffff88053484a000, task ffff880534aae100) Call Trace: [] srp_post_send+0x65/0x70 [ib_srp] [] srp_queuecommand+0x1cf/0x3e0 [ib_srp] [] scsi_dispatch_cmd+0x101/0x280 [scsi_mod] [] scsi_request_fn+0x411/0x4d0 [scsi_mod] [] __blk_run_queue+0x27/0x30 [] blk_execute_rq_nowait+0x82/0x110 [] blk_execute_rq+0x62/0xf0 [] scsi_execute+0xe8/0x190 [scsi_mod] [] scsi_execute_req+0xa3/0x130 [scsi_mod] [] scsi_probe_lun+0x17a/0x450 [scsi_mod] [] scsi_probe_and_add_lun+0x156/0x480 [scsi_mod] [] __scsi_scan_target+0xdf/0x1f0 [scsi_mod] [] scsi_scan_host_selected+0x183/0x1c0 [scsi_mod] [] scsi_scan+0xdb/0xe0 [scsi_mod] [] store_scan+0x13/0x20 [scsi_mod] [] sysfs_write_file+0xcb/0x160 [] vfs_write+0xce/0x140 [] sys_write+0x53/0xa0 [] system_call_fastpath+0x16/0x1b [<00007f611c9d9300>] 0x7f611c9d92ff Reported-by: Max Gurtuvoy Signed-off-by: Bart Van Assche Reviewed-by: Mike Christie Cc: Signed-off-by: James Bottomley --- drivers/scsi/scsi_lib.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'drivers/scsi') diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 54d7a6cbb98a..b1a263137a23 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1311,9 +1311,11 @@ scsi_prep_state_check(struct scsi_device *sdev, struct request *req) "rejecting I/O to dead device\n"); ret = BLKPREP_KILL; break; - case SDEV_QUIESCE: case SDEV_BLOCK: case SDEV_CREATED_BLOCK: + ret = BLKPREP_DEFER; + break; + case SDEV_QUIESCE: /* * If the devices is blocked we defer normal commands. */ -- cgit v1.2.3-59-g8ed1b